Wanderlust

If you really want to know a city, sit down and have coffee with it. In a world taken over by the expensive coffee culture, it’s hard not to find them in most cities. And here in Makati, I found myself inside one of its glorified cafes. In the Philippines’ business district, amidst towering buildings, people go about their daily business unconcerned with the rain or the traffic of people. Along the busy streets of a city that never sleeps, a torrent of vechicles and people continuously passing through. And for people like me, that’s all we do. Always just passing through regardless of whether or not there is a destination. Always the foreigner.

For me there are two extreme kinds of people: the settlers and the travellers.The former constantly pinned down either by chance, choice or circumstance; too comfortable to move on. The latter constantly overtaken by wanderlust, too facinated with the adventure to stop. And at some point in our life we become one or the other, the rest of the time we are a little of both. Just passing through.

The thing is, for the travellers, when they run they feel like it would never end. But everybody stops running sooner or later, be it away or towards something. Everyone knows that every journey ends and nobody knows it better than the traveller — constantly saying goodbye, constantly moving on. But you see, travellers continue the journey regardless because it is always worth it. Because every new city or country or place is like a love affair when time is your mistress. Each adventure a staging of a great story of love. I guess that’s why they call it wanderlust because it inspire passion and desire that can consume you.

When you travel you’ll always know a fellow traveller. Travellers often find each other. I’m not really sure how. I never really thought about it. Maybe it’s how their eyes takes in their surroundings — always eager, learning and fascinated. Maybe it’s the way they walk — always a tiny bit slower than everyone else as though getting to know the ground they’re walking on.

You’ll see them everywhere around you if you just care to notice. They are people like you or me. They have jobs, bills, home or even family but they also have a secret life. And deep down in their hearts, there is that wanderlust that they can never seem to satiate. So every now and then they give in to it. And they walk the city as though seeing it again for the first time.

John Nash’s Letter to the NSA

imyjimmy:

The National Security Agency (NSA) has recently declassified an amazing letterthat John Nash sent to it in 1955.  It seems that around the year 1950 Nash tried to interest some US security organs (the NSA itself was only formally formed only in 1952) in an encryption machine of his design, but they did not seem to be interested.  It is not clear whether some of his material was lost, whether they ignored him as a theoretical professor, or — who knows — used some of his stuff but did not tell him.  In this hand-written letter sent by John Nash to the NSA in 1955, he tries to give a higher-level point of view supporting his design:

In this letter I make some remarks on a general principle relevant to enciphering in general and to my machine in particular.

He tries to make sure that he will be taken seriously:

I hope my handwriting, etc. do not give the impression I am just a crank or circle-squarer.  My position here is Assist. Prof. of Math.  My best known work is in game theory (reprint sent separately).

He then goes on to put forward an amazingly prescient analysis anticipating computational complexity theory as well as modern cryptography.  In the letter, Nash takes a step beyond Shannon’s information-theoretic formalization of cryptography (without mentioning it) and proposes that security of encryption be based on computational hardness — this is exactly the transformation to modern cryptography made two decades later by the rest of the world (at least publicly…).  He then goes on to explicitly focus on the distinction between polynomial time and exponential time computation, a crucial distinction which is the basis ofcomputational complexity theory, but made only about a decade later by the rest of the world:

So a logical way to classify enciphering processes is by t he way in which the computation length for the computation of the key increases with increasing length of the key. This is at best exponential and at worst probably at most a relatively small power of r,  or , as in substitution ciphers.

He conjectures the security of a family of encryption schemes.  While not totally specific here, in today’s words he is probably conjecturing that almost all cipher functions (from some — not totally clear — class) are one-way:

Now my general conjecture is as follows: for almost all sufficiently complex types of enciphering, especially where the instructions given by different portions of the key interact complexly with each other in the determination of their ultimate effects on the enciphering, the mean key computation length increases exponentially with the length of the key, or in other words, the information content of the key.

He is very well aware of the importance of this “conjecture” and that it implies an end to the game played between code-designers and code-breakers throughout history.  Indeed, this is exactly the point of view of modern cryptography.

The significance of this general conjecture, assuming its truth, is easy to see.  It means that it is quite feasible to design ciphers that are effectively unbreakable.  As ciphers become more sophisticated the game of cipher breaking by skilled teams, etc., should become a thing of the past.

He is very well aware that this is a conjecture and that he cannot prove it.  Surprisingly, for a mathematician, he does not even expect it to be solved.  Even more surprisingly he seems quite comfortable designing his encryption system based on this unproven conjecture.  This is quite eerily what modern cryptography does to this day: conjecture that some problem is computationally hard; not expect anyone to prove it; and yet base their cryptography on this unproven assumption.

The nature of this conjecture is such that I cannot prove it, even for a special type of ciphers.  Nor do I expect it to be proven.

All in all, the letter anticipates computational complexity theory by a decade and modern cryptography by two decades.  Not bad for someone whose “best known work is in game theory”.  It is hard not to compare this letter to Goedel’s famous 1956 letter to von Neumann also anticipating complexity theory (but not cryptography).  That both Nash and Goedel passed through Princeton may imply that these ideas were somehow “in the air” there.

ht: this declassified letter seems to have been picked up by Ron Rivest who posted it on his course’s web-site, and was then blogged about (and G+ed) by Aaron Roth.

Edit: Ron Rivest has implemented Nash’s cryptosystem in Python.  I wonder whether modern cryptanalysis would be able to break it.

Source: Turing’s Invisible Hand

Profiles

We are all stories: stories we tell others, stories we tell ourselves. Our lives are stories of stories of stories and we like to tell ourselves that we are the camera behind the camera behind the camera — that our story is some sort of ultimate truth. And in this time and age the stories have become shorter and shorter with most told in 160 characters or less. In a time when we digitally curate our stories, choosing the ones we tell on countless networks, can we ever know the truth about someone? Aren’t we all showing the best possible version of ourselves?

In a world where presentation is everything, we try to present ourselves in the best possible light. People judge and are judged based on public profiles. Everyone edits themselves which makes me wonder whether I am connected with real people, or just the people they wish they were.

There is an intimacy along with the obvious awkwardness and indifference. The truth merely shattered illusions and in some respects I don’t think anyone involved can possibly be genuinely happy. We see the things we want to see along with what we want others to see about us. We try to stand out, impress and out shine each other. It makes me wonder if anyone is actually paying attention. We spend more time viewing our own profile (save from the one/s we are currently “stalking”) that makes me wonder if people really pay attention to other people’s profile.

To the Facebook famous question, “Who viewed your profile?” I’m sure I didn’t.